Chapter 7 — Diseases of the Eye and Adnexa
Glaucoma type, laterality and stage — where the number of codes depends on whether the classification happens to provide a bilateral code — plus the blindness defaults.
Chapter 7 has two guidelines: glaucoma and blindness. The glaucoma rules are the only place in ICD-10-CM where laterality, type and a 7th-character stage interact, and the answer changes depending on whether the classification happens to provide a bilateral code for the type you are coding.
How many glaucoma codes, and which ones?#
Assign as many codes from category H40 as needed to identify the type of glaucoma, the affected eye and the glaucoma stage.
| Situation | Assign |
|---|---|
| Bilateral glaucoma, both eyes the same type and stage, and a bilateral code exists | Only the code for the type of glaucoma, bilateral, with the 7th character for the stage |
Bilateral glaucoma, both eyes the same type and stage, but the classification provides no bilateral code — subcategories H40.10 and H40.20 | Only one code for the type of glaucoma, with the appropriate 7th character for the stage |
| Bilateral glaucoma, each eye a different type or stage, and the classification distinguishes laterality | The appropriate code for each eye, rather than the bilateral code |
Bilateral glaucoma, each eye a different type, and the classification does not distinguish laterality — H40.10, H40.20 | One code for each type of glaucoma, with the appropriate 7th character for the stage |
Bilateral glaucoma, both eyes the same type but different stage, and the classification does not distinguish laterality — H40.10, H40.20 | A code for the type of glaucoma for each eye, with the 7th character for the specific stage documented for that eye |
| Patient admitted with glaucoma and the stage progresses during the admission | The code for the highest stage documented |
| 7th character | Meaning | When to use |
|---|---|---|
4 | Indeterminate stage | A clinical finding — the glaucoma's stage cannot be clinically determined. Assignment is based on the clinical documentation |
0 | Unspecified stage | A documentation gap — there is no documentation regarding the stage of the glaucoma |
Blindness and low vision#
| Documentation | Assign |
|---|---|
| “Blindness” or “low vision” of both eyes, visual impairment category not documented | H54.3 Unqualified visual loss, both eyes |
| “Blindness” or “low vision” in one eye, visual impairment category not documented | A code from H54.6- Unqualified visual loss, one eye |
| “Blindness” or “visual loss” documented with no information about whether one or both eyes are affected | H54.7 Unspecified visual loss |
Practice questions#
Q1A patient has bilateral primary open-angle glaucoma. The right eye is documented as moderate stage and the left eye as severe stage. The classification does not distinguish laterality for this subcategory. What is assigned?
- AOne code with the 7th character for severe stage
- BOne code for the type of glaucoma for each eye, each with the 7th character for that eye's stage
- CThe bilateral code with the 7th character for the highest stage
- DOne code with 7th character 0
Show answer & rationale
Correct answer: B. One code for the type of glaucoma for each eye, each with the 7th character for that eye's stage
Rationale. Guideline I.C.7.a.3 states that when a patient has bilateral glaucoma and each eye is documented as having the same type but a different stage, and the classification does not distinguish laterality, assign a code for the type of glaucoma for each eye with the seventh character for the specific glaucoma stage documented for each eye.
Q2The ophthalmologist documents that the stage of the patient's glaucoma cannot be clinically determined. Which 7th character applies?
- A0
- B4
- C9
- DX
Show answer & rationale
Correct answer: B. 4
Rationale. Guideline I.C.7.a.5 states that assignment of the seventh character 4 for indeterminate stage should be based on the clinical documentation, and is used for glaucomas whose stage cannot be clinically determined. It should not be confused with the seventh character 0, unspecified, which is assigned when there is no documentation regarding the stage of the glaucoma.
Q3A patient is admitted with glaucoma documented as mild stage. During the admission the documentation records progression to moderate stage. What is assigned?
- AThe code with the 7th character for mild stage
- BThe code with the 7th character for the highest stage documented
- CTwo codes, one for each stage
- DThe code with 7th character 4
Show answer & rationale
Correct answer: B. The code with the 7th character for the highest stage documented
Rationale. Guideline I.C.7.a.4 states that if a patient is admitted with glaucoma and the stage progresses during the admission, assign the code for the highest stage documented. This mirrors the dementia rule at I.C.5.d and contrasts with the pressure ulcer rule at I.C.12.a.6, which requires two codes.
Q4“Low vision, both eyes” is documented with no visual impairment category. What is assigned?
- A
H54.7 - B
H54.3 - CA code from
H54.6- - D
H54.0
Show answer & rationale
Correct answer: B. H54.3
Rationale. Guideline I.C.7.b states that if blindness or low vision of both eyes is documented but the visual impairment category is not documented, assign H54.3, unqualified visual loss, both eyes. H54.6- is for one eye without a category, and H54.7 is for visual loss documented with no information about whether one or both eyes are affected.
Q5A patient has bilateral glaucoma of the same type and the same stage, and the classification does provide a bilateral code for that type. What is assigned?
- ATwo codes, one for each eye
- BOnly the bilateral code, with the 7th character for the stage
- CThe bilateral code plus a unilateral code for each eye
- DOne unilateral code
Show answer & rationale
Correct answer: B. Only the bilateral code, with the 7th character for the stage
Rationale. Guideline I.C.7.a.2 states that when a patient has bilateral glaucoma and both eyes are documented as being the same type and stage, and there is a code for bilateral glaucoma, report only the code for the type of glaucoma, bilateral, with the seventh character for the stage. Where no bilateral code exists for that type, the same guideline directs that only one code for the type is reported.
Scenarios#
An ophthalmology record documents primary open-angle glaucoma of the right eye, moderate stage, and primary angle-closure glaucoma of the left eye, severe stage. The relevant subcategories do not distinguish laterality.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | H40.11X2 | Primary open-angle glaucoma with 7th character for moderate stage — verify the subcategory and 7th character in the Tabular List |
| 2 | H40.2XX3 | The applicable primary angle-closure glaucoma code with the 7th character for severe stage — verify in the Tabular List |
Rationale. Guideline I.C.7.a.3 states that when a patient has bilateral glaucoma and each eye is documented as having a different type, and the classification does not distinguish laterality, assign one code for each type of glaucoma with the appropriate seventh character for the stage. Guideline I.C.7.a.1 permits as many codes from H40 as needed to identify the type, the affected eye and the stage. Always confirm whether the specific subcategory you are using carries laterality before deciding how many codes are needed.
Guideline: Section I.C.7.a.1, I.C.7.a.3
A patient with bilateral age-related nuclear cataracts had the right eye operated on eight weeks ago, with complete resolution on that side. She now presents for surgery on the left eye.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | H25.12 | Age-related nuclear cataract, left eye — the unilateral code |
Rationale. This is the second half of the guideline's own cataract example at Section I.B.13. At the first encounter the bilateral code is assigned because the condition still exists on both sides. At the second encounter, once one side has been treated and the condition no longer exists there, the appropriate unilateral code is assigned for the side where the condition still exists. Had the first surgery not completely resolved the condition, the bilateral code would still be appropriate.
Guideline: Section I.B.13
A record for an unrelated encounter documents “blind” with no statement of which eye or eyes are affected, and no visual impairment category. Nothing elsewhere in the record clarifies laterality and the provider is not available.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | H54.7 | Unspecified visual loss |
Rationale. Guideline I.C.7.b provides that if blindness or visual loss is documented without any information about whether one or both eyes are affected, H54.7 unspecified visual loss is assigned. Section I.B.13 adds the broader principle that codes for an unspecified side should rarely be used, and only where the documentation is insufficient and clarification cannot be obtained — which is the case here. Section I.B.18 confirms that unspecified codes have acceptable, even necessary, uses.
Guideline: Section I.C.7.b, I.B.13, I.B.18
Primary sources#
- ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027CMS — the source document for every page on this site (effective 1 Oct 2026)
- NCHS ICD-10-CM files — Tabular List, Index, POA exempt listOfficial code files, addenda and the list of codes exempt from POA reporting
- ICD-10 Coordination and Maintenance CommitteeWhere code proposals are debated; agendas, summaries and meeting materials
- CMS ICD-10 homeCode sets, transition guidance and Medicare coding policy
- AHA Coding ClinicOfficial coding advice from the AHA Central Office — subscription required
- HHS OIG Work PlanActive audit topics — useful for prioritising internal coding audits
- MEDESUN Medical Coding AcademyTraining, credential preparation and audit services by the author